Treasuries, agency bonds, municipal bonds and corporate bonds are the major U.S. bond sectors. Internationally, there is sovereign debt, corporate debt, developed, less developed and emerging market bond issuers. There’s also the distinction between short-term, intermediate-term and long-term maturities.
Falling interest rates mean higher bond prices. It’s conceivable that the bull market in bonds isn’t quite over.
The U.S. Treasury is considering issuing a 50-year Treasury maturity.